The present invention relates to a device for slicing loaves and other bakery products, such as for example cakes and pastries. These bakery products may optionally be completely frozen, or frozen just on the outside, in particular in order to allow cutting of soft bakery products or of bakery products with a filling which is soft at room temperature, such as pies. In addition, the invention relates to a cutting-blade carrier for a device of this kind and to the cleaning of the cutting blades of a device of this kind.
A known device for slicing loaves is described in GB-1,464,604. This device is provided with two cutting-blade carriers, which are disposed one behind the other, as seen in the passage direction of the loaves. The two cutting-blade carriers are each guided in a straight line, substantially perpendicular to the passage direction of the loaves, in the frame of the device and are moved in a reciprocating manner in opposite phases.
In generally known bread-cutting devices, the cutting-blade carriers are driven with a rectilinear, reciprocating movement, which has an amplitude of between 30 and 45 millimeters and a frequency of 700 to 800 reciprocating movements per minute. Another known device has only one cutting-blade carrier, which is driven with a rectilinear, reciprocating movement which has an amplitude of 3 millimeters and a frequency of approximately 3000 reciprocating movements per minute.
In practice, the known devices have proven unsatisfactory. Particularly if the bread was baked shortly before, it adheres to the cutting blades, with the result that it is desirable, not to say necessary, to regularly remove the bread material which adheres to the cutting blades during the cutting operation. This is because bread residues adhere to the cutting blades to an ever increasing extent as the cutting blades become dirtier.
For the purpose of cleaning the cutting blades, it is generally known in the case of the devices of the large-amplitude type to provide one or more scraper members, which are disposed outside the path through the cutting device for the loaves, the cutting blades being scraped clean on moving past a cutting member. In practice, the loaves to be cut are frequently so high, approximately 15-20 centimeters as seen in the longitudinal direction of the cutting blades, that the central part of the bread-cutting length of the cutting blades does not move past one of the scraper members in these known devices, and is therefore not cleaned. In the case of the known small-amplitude device, it is impossible to clean the cutting blades in this manner during cutting of the bread.
It is also known to apply a small quantity of an edible lubricant to the cutting blades during the cutting operation, particularly when cutting bread with a low fat content. The application of lubricant can also only take place outside the path of the loaves. Owing to the considerations outlined in the preceding paragraph, it is clear that in many cases the known devices do not allow satisfactory lubrication of the cutting blades.
A further drawback of the known devices is that the cutting operation entails an undesirably high loss of bread material, owing to the formation of crumbs. The crumbs are mainly formed as a result of the contact between the sides of the cutting blades and the bread, in particular at the location of the transitions between that edge of each cutting blade which is provided with cutting formations and the substantially flat sides of this cutting blade.
The object of the present invention is to eliminate the abovementioned problems. Furthermore, the invention aims to eliminate a considerable number of other drawbacks of the known devices. These drawbacks include the fact that the known cutting-blade carriers are expensive and that exchanging a cutting-blade carrier requires a maintenance person and takes up considerable time, during which time cutting cannot take place. The present invention also aims to provide measures which improve the cleaning of the cutting blades, so that the cutting blades last longer and fewer crumbs are formed.
According to a first aspect, the present invention provides a device for slicing loaves and other bakery products, comprising a frame, which is provided with support means for the loaves, which support means define a path for the loaves through the device, a cutting-blade carrier, which holds a plurality of thin, elongate cutting blades next to one another and at a distance from one another, each cutting blade having a cutting edge which has cutting formations for cutting the loaf, drive means for creating a reciprocating movement of the cutting blades with respect to the support means for the loaves, which reciprocating movement is parallel to the longitudinal direction of the cutting blades, characterized in that the drive means of the cutting-blade carrier provide a first movement, which is characterized by a first amplitude in the longitudinal direction of the cutting blades and a first frequency, and also provide a second movement, which is characterized by a second amplitude in the longitudinal direction of the cutting blades and a second frequency, the first amplitude being greater than the second amplitude and the first frequency being lower than the second frequency, and in that the drive means are designed to superimpose the first movement and the second movement to form a resultant movement, and in that the drive means drive the cutting blades with the resultant movement, which preamble is based on GB-1,464,604, which device is characterized by the above-described characterizing part of the description.
The characteristic part of the device provides for the movement of each cutting-blade carrier to be the resultant of the low-frequency first movement, which may also be an intermittently executed movement, having a large amplitude, on the one hand, and a high-frequency, preferably continuous, second movement having a small amplitude, on the other hand.
In one preferred embodiment, the cleaning means may comprise, for example, two cleaning devices, one below and one above the path for the loaves, in which case, for example, the position of the top cleaning device is adjustable with respect to the support means for the loaves, so that the position of the top cleaning device can be matched to the height of the loaves to be cut. In a variant, only one cleaning device may be provided, for example at a short distance below the path for the loaves. The invention provides for the cutting action of the cutting blades to be effected substantially by the second movement and for the first movement to serve primarily to allow the cutting blades to move past the cleaning means over their entire bread-cutting length.
In another preferred embodiment, the effect is achieved that the cutting blades not only move in a rectilinear, reciprocating manner in the longitudinal direction of the cutting blades, as in the case of known devices, but also each cutting blade executes small loop movements with a high frequency. This loop movement is very advantageous for the cutting action of the cutting blades when cutting bread and other bakery products. The loop movement is also advantageous if the sides of the cutting blades bear against scraper surfaces of a scraper member, because in this case a type of polishing effect is achieved.
The advantageous direction of the loop-like movement is an arc-like path from a top point situated furthest away from the support means towards a bottom point situated closest to the support means, with a first deviation with respect to the imaginary straight line between the top point and the bottom point, which first deviation is directed counter to the passage direction, and in which the loop-like movement also describes an arc-like path from the bottom point to the top point, with a second deviation with respect to the imaginary straight line between the bottom point and the top point, which second deviation is likewise directed counter to the passage direction, and in which the first deviation is greater than the second deviation, the loaf to be cut remaining in a stable position on the support means.
Values which are advantageous in practice include those in which the first amplitude lies in the order of magnitude of a few centimeters and the second amplitude lies in the order of magnitude of one or several millimeters, the magnitude of the first amplitude being dependent substantially on the height of the loaf to be cut and on the arrangement of any cleaning means for the cutting blades. The second amplitude is preferably small.
Values which are advantageous in practice include those in which the first frequency lies in the order of magnitude of one or more strokes per second and the second frequency lies in the order of magnitude of several tens of, preferably more than a hundred, strokes per second, and it should be noted that in principle the first movement does not have to be a continuous movement, but may also be a stepwise movement, since the cutting action is effected substantially by means of the second movement.
The position of the cutting formations according to another aspect of the present invention is considerably closer together, i.e., with a finer toothing, than that which is used in the case of the known devices. The distance between the cutting formations is preferably less than the second amplitude. Moreover, each of the cutting blades is preferably provided on the cutting edge with cutting formations situated at regular distances from one another, the distance between adjacent cutting formations lying between 0.5 and 4 millimeters.
In another preferred embodiment in which the drive means for the cutting-blade carrier comprise an intermediate carrier, which is disposed between the frame and the cutting-blade carrier, in which the intermediate carrier is held in the frame such that it can move in a reciprocating manner substantially parallel to the longitudinal direction of the cutting blades, and in which the intermediate carrier is designed to support the cutting blades such that they can move with respect to the intermediate carrier, the drive means comprising first drive means, which are disposed between the frame and the intermediate carrier for driving the intermediate carrier such that it moves with respect to the frame, and also second drive means, which are disposed between the intermediate carrier and the cutting blades so as to drive the cutting blades such that they move with respect to the intermediate carrier, the second drive means only have to drive the relatively lightweight cutting-blade carrier and associated holding means, without having to cover a long drive path.
The invention makes it possible for there to be only one single cutting-blade carrier present, instead of two, as in the known devices. This is possible because in the device according to the invention the bread is not dragged along by the cutting blades which move with a small amplitude and a high frequency and are preferably regularly cleaned during the cutting operation. However, a variant of the device according to the invention comprises two cutting-blade carriers which are disposed one behind the other in the passage direction of the loaves, in which case an advantageous embodiment provides for the two cutting-blade carriers each to be driven with an identical second movement, but in opposite phases, and for the two cutting-blade carriers to be driven by common first drive means providing the first movement.
According to a second aspect, the present invention provides a device for slicing loaves and other bakery products, comprising a frame, which is provided with support means for the loaves, which support means define a path for the loaves through the device, a cutting-blade carrier, which holds a plurality of thin, elongate cutting blades next to one another and at a distance from one another, each cutting blade having a cutting edge which has cutting formations for cutting the loaf, which cutting-blade carrier has a top attachment body which is common to the cutting blades and a bottom attachment body which is common to the cutting blades, one end of each cutting blade being connected to the bottom attachment body and the other end of each cutting blade being connected to the top attachment body, tensioning means being provided so as to effect and maintain an axial operational tension in each cutting blade during the cutting operation, drive means for creating a reciprocating movement of the cutting blades with respect to the support means for the loaves, which reciprocating movement is parallel to the longitudinal direction of the cutting blades, characterized in that the top attachment body and the bottom attachment body of the cutting-blade carrier are displaceable with respect to one another, in that the drive means are provided with top holding means for releasably holding the top attachment body of the cutting-blade carrier and with bottom holding means for releasably holding the bottom attachment body of the cutting-blade carrier, and in that the tensioning means are designed so as to change the distance between the top holding means and the bottom holding means, so that after the top and bottom attachment bodies have respectively been arranged in the top and bottom holding means the distance between the top and bottom holding means can be increased, bringing about the axial operational tensioning of the cutting blades. The known cutting-blade carriers, an example of which is described in GB-2,007,971, comprise a rectangular framework, in which the cutting blades are fixed under tensile stress. The cutting-blade carriers are of robust and strong design, in order to be able to withstand the total tensile stress in all the cutting blades. A usual tensile stress is approximately 500 N per cutting blade, so that in the case of 40 cutting blades the side bars of the framework each have to be able to withstand a compressive force of 10 kN. On the other hand, the cutting-blade carrier must be lightweight, in order to limit the acceleration and retardation forces occurring at the reciprocating-movement frequency which is required for the cutting action. In order to fulfill both demands, the known cutting-blade carriers are generally produced from expensive metal alloys, such as magnesium alloys.
The measures make possible a considerably more lightweight, and in particular a less expensive, design of the cutting-blade carrier. In the device, the cutting-blade carrier no longer serves to hold the cutting blades at the required operational tension, as has hitherto been the case, but merely as a temporary holder for the cutting blades. The cutting blades are tensioned after the cutting-blade carrier has been placed in the device, with the aid of tensioning means which form part of the cutting device. The cutting-blade carrier can therefore be designed as a lightweight and simple holder which holds the cutting blades in the desired position and can be handled as a single unit with the cutting blades held therein. As a result of this measure, it is economically possible to keep a stock of a plurality of cutting-blade carriers with cutting blades therein for a single cutting device, for example to keep a separate cutting-blade carrier, with a suitable distance between the cutting blades, for each type of bread to be cut.
The measure according to an additional embodiment includes one in which the top holding means and the bottom holding means each comprise an elongate holding member which extends transversely to the passage direction and is provided with a groove, extending in its longitudinal direction, with a slide-in opening at one end of the holding member in question, which groove is open on the side facing towards the other holding member, so that the attachment bodies of the cutting-blade carrier can be slid into the holding members, which makes it possible to slide the cutting-blade carrier into the device transversely to the passage direction of the loaves, with the result that one cutting-blade carrier can be replaced quickly and easily with another.
A cutting-blade carrier for a device for slicing loaves and other bakery products, comprising a top bar and a bottom bar which is substantially parallel thereto, the top bar and the bottom bar being designed for attaching between them a plurality of thin, elongate cutting blades which are positioned next to one another and at a distance from one another, the top bar and the bottom bar being connected to one another by means of spacer means so as to form a unit which can be handled as a single entity, characterized in that the spacer means allow the top bar and the bottom bar to move apart, so as to tension the cutting blades with an axial operating tension which is suitable for cutting the loaf. The cutting-blade carrier can be used to realize the device according to the present invention. The spacer means of the cutting-blade carrier may take many different forms, for example the form of connecting elements which are placed between the top and bottom attachment bodies and provide a low resistance to extension, for example made of plastic material. It would also be possible to provide for the spacer means to be attached in a releasable manner to the top and bottom attachment bodies and to be removed entirely after placing the cutting-blade carrier in the cutting device, if appropriate automatically using the device itself.
According to a third aspect, the present invention provides a device for slicing loaves and other bakery products, comprising a frame, which is provided with support means for the loaves, which support means define a path for the loaves through the device, a cutting-blade carrier, which holds a plurality of thin, elongate cutting blades next to one another and at a distance from one another, each cutting blade having a cutting edge which has cutting formations for cutting the loaf, drive means for creating a reciprocating movement of the cutting blades with respect to the support means for the loaves, which reciprocating movement is parallel to the longitudinal direction of the cutting blades, cleaning means for the cutting blades being provided, in order to clean the cutting blades during cutting of the loaves, which cleaning means are disposed outside the path for the loaves which is defined by the support means, the cleaning means comprising a scraper member, which extends transversely to the cutting blades and is provided with a plurality of slot openings, each for the passage of a cutting blade, the scraper member forming a scraper surface on either side of each cutting blade, which surface is intended to scrape along the adjacent side of the cutting blade, characterized in that displacement means are provided so as to displace the scraper member with respect to the cutting blades in a reciprocating manner substantially transversely to the cutting blades. In bread-cutting devices, it is known to use scraper members whose slot openings are at an angle to the longitudinal direction of the cutting blades, so that on one side of the cutting blade the top edge of the slot opening forms a scraper surface, and on the other side the bottom edge forms a scraper surface which is in contact with the cutting blade. Owing to the inevitable wear to the scraper member at the location of the scraper surfaces, the contact pressure between the scraper surfaces and the cutting blade will gradually decrease, and the cleaning action is reduced. The displacement means according to the present invention enable one or other scraper surface alternately to be pressed against the cutting blade with an adjustable larger force, even if the scraper surfaces have already been worn away to some extent. As a result, the cutting blade is cleaned very effectively and the scraper member can still be used even if wear has taken place.
According to a fourth aspect, the present invention provides a device for slicing loaves and other bakery products, comprising a frame, which is provided with support means for the loaves, which support means define a path for the loaves through the device, a cutting-blade carrier, which holds a plurality of thin, elongate cutting blades next to one another and at a distance from one another, each cutting blade having a cutting edge which has cutting formations for cutting the loaf, drive means for creating a reciprocating movement of the cutting blades with respect to the support means for the loaves, which reciprocating movement is parallel to the longitudinal direction of the cutting blades, cleaning means for the cutting blades being provided, in order to clean the cutting blades during cutting of the loaves, which cleaning means are disposed outside the path for the loaves which is defined by the support means, the cleaning means comprising a scraper member, which extends transversely to the cutting blades and is provided with a plurality of slot openings, each for the passage of a cutting blade, the scraper member forming a scraper surface on either side of each cutting blade, which surface is intended to scrape along the adjacent side of the cutting blade, characterized in that one or more channels are arranged in the scraper member, which channels have an outlet port at each of the slot openings in the scraper member, and in that air-supply means are provided for supplying compressed air to the channels, which prevents contaminants scraped off a cutting blade from collecting in the slot opening in the scraper member.
An embodiment of this aspect of the present invention, in which the air-supply means comprise a stationarily disposed air-injection member, which extends past the reciprocatingly moveable scraper member and is provided with a plurality of air-blowing outlets, and in which the scraper member is provided with an air-inlet port opposite each air-blowing outlet of the air-injection member, each air-inlet port adjoining an associated channel in the scraper member, which channel has an outlet port at a number of the slot openings in the scraper member, makes it possible to combine the advantages of the devices of the third and fourth aspects of the present invention with one another, with the result that very effective cleaning of the cutting blades is achieved.
According to a fifth aspect, the present invention provides a device for reducing time for exchanging blades. As has already been mentioned above, it is desirable to reduce the time required for exchanging a cutting-blade carrier. The measures according to this aspect of the present invention contribute to reducing this time. These measures are particularly advantageous in combination with the previously described devices.
According to a sixth aspect, the present invention provides a cutting-blade carrier. In the case of the known cutting-blade carriers, all the adjustable attachment members are arranged on the top bar and all the fixed attachment members are arranged on the bottom bar of the cutting-blade carrier. However, the adjustable attachment members take up a larger space than that which is required for the fixed attachment members. The alternate arrangement allows a minimal distance between the cutting blades.
According to a seventh aspect, the invention provides a device with a provision for the scraper members which are required for scraping a set of cutting blades to be exchanged at the same time as the cutting-blade carrier, all this taking place automatically. This is possible as a result of the scraper members, of which there are usually two per set of cutting blades, already being attached beforehand temporarily to the cutting-blade carrier, and as a result of providing the cutting device with a suitably designed mechanism which, after the cutting-blade carrier has been placed in the device, grips the scraper members, moves them to their desired position and then holds them fast. If appropriate, there may be provision for the mechanism to fix the scraper members back on the cutting-blade carrier before the cutting-blade carrier is removed, so that these scraper members are removed together with the cutting-blade carrier. This design is particularly advantageous in combination with the designs of the previous devices.
According to an eighth aspect, the invention provides a device with a design of slot openings in the scraper member prevents wear causing the scraper surfaces to wear down to recesses in the walls of the slot openings. In practice, this would make it impossible to clean a new set of cutting blades with the same scraper member, since the cutting blades also become slightly worn and therefore new cutting blades would not fit in the worn-out recesses. This measure is particularly advantageous in combination with a previous device, in which the cutting blades perform a small loop-like movement in their plane.